Celebrated as one of the most idyllic destinations within St. Paul, Como Lake offers 1.7-miles of walking paths, a restaurant, outdoor stage and wedding pavilion — just a few of the features that draw some 4.3 million visitors annually.

The 70-acre lake also borders a popular zoo and conservatory, an amusement park, an 18-hole golf course and an residential neighborhood.

So what’s not to love? For starters, Como Lake can smell bad — and on more than the rare occasion. It’s an odor problem poised to get worse as invasive weeds mount an attack. And that’s the opinion of some of its biggest fans.

“In July and August, it can smell very bad,” said City Council President Amy Brendmoen, who regularly jogs or speed-walks the lake with constituents.

The primary culprit is the curly-leaf pond weed, which rests below the surface of the winter ice, blocking sunlight to native plants and biding its time. By summer, the smell of plant death is afoot.

“It starts growing when the ice is still on the lake and it blooms early. And then it rots,” Brendmoen said. “It has been a problem forever.”

The pond weed, discovered at Como Lake in the early 90s, has hit critical mass, overpowering all other forms of native plant life, according to researchers. It’s also compounded another struggle for the lake: phosphorous loads. On top of blown leaves and grass clippings, discharge from 22 storm-sewer outfalls and run-off from urban development have left the shallow lake bottom laden with phosphorous, which leaks out of sediment into the water to feed ugly algae blooms.

It’s a problem that is getting worse, according to nearby residents. “In the summer, it’s hideous,” said Gordon Wrobel, who has volunteered for years with lake clean-up efforts. “The algae blooms are really substantial. And it’s really unfortunate, because Como Lake is really a jewel of this whole state. There’s millions of visitors that come to Como Park every year.”

The Capitol Region Watershed District has traded notes with Ramsey County officials about lake conditions since the 1990s, and all agree it’s time to take action. Efforts to capture and clean run-off over the past 20 years have reduced loads by 20 percent, but that’s still three times larger than the state standard.

“The whole lake bed has phosphorous locked up into it,” said Britta Belden, project manager with the Capitol Region Watershed District. “As it releases, we have algae that is actively consuming it and growing … which is why the lake looks green mid-summer well into October.”

Environmental experts describe the lake as living in “a very steady state of unhealthiness,” Brendmoen said. “It only has medium-sized fish. Little fish normally eat the algae, but there’s no little fish. And there’s no big fish because they can’t survive.”

ALUM TREATMENT

After years of upturned noses, a solution to Como Lake’s odor-and-algae bloom problem may finally be in sight. The Capitol Region Watershed District, a St. Paul-based watershed management organization and local unit of government, completed a Como Lake management plan a year ago that spells out two major lake restoration projects: a multi-year application of a weed-killing herbicide and a one-time injection of a phosphorous-consuming baking powder.

That’s right — baking powder.

For four to 10 days in May, expect to see a boat touring Como Lake, injecting the water with aluminum sulfate, or alum, a colorless astringent derived from aluminum and potassium. The goal is to blanket the lake bottom and smother the phosphorous so it can’t release into the water, much like an antacid neutralizes excess stomach acid. Alum is sold in stores for pickling and crisping vegetables, and some swear by it for skin tightening and even acne removal.

The hope is the $150,000 project will knock out the phosphorous problem in a single stretch, immediately cutting down on algae blooms.

“They’ll be able to see immediate results,” Belden said. “As the alum is applied, it’s also binding up phosphorous that is in the water. We’ll reevaluate it in years to come to see if additional treatments are needed.”

In short, “Como Lake is getting a chemical makeover,” said Brendmoen, who is optimistic the treatment will take. “It should result in a dramatically different looking and smelling Como Lake.”

That’s a relief to Como resident Janna Caywood, who for years has helped mobilize a network of more than 70 households to help steward water-quality projects.

“Those of us who live here have been trying to focus on what is the role of residents to reduce the amount of phosphorous coming in from the outside,” said Caywood, acknowledging that those efforts simply haven’t been enough. “Now they’ve decided to focus on what’s arguably a harder problem — the internal loading of phosporous. The alum treatment, I do think it makes sense. The impact to the overall ecology of the lake is minimal.”

“Even to recreate on the lake, canoeing, kayaking, stand-up paddle board, that’s less appealing when the lake looks disgusting and smells disgusting,” Caywood added. “Some summers it’s not as bad.”

MULTI-YEAR FLURIDONE TREATMENT

The antacid treatment is only step one. To kill the pond weed, Capitol Region Watershed has recommended an aquatic herbicide that would be applied annually for the next several years. The herbicide, Fluridone, is one that’s commonly used throughout the state to kill aquatic millfoil, and the Minnesota Department of Natural Resources has approved up to seven years of treatments, if necessary. The projected cost is $6,000.

“We’re set to begin that in April 2020 … as soon as the ice goes out, so we can target that curly leaf pond weed and hopefully intercept the plant in its growing season,” said Belden, who envisions 60 days of treatment at low dosages. “With that low dose, there are no restrictions for humans, pets, wildlife or fish in contact with the water.”

Belden said Capitol Region Watershed examined a number of options, including physically removing the pond weed with a mechanical harvester, but that approach was more likely to spread the weed than remove it. Even the herbicide isn’t expected to fully eliminate it. The goal is to kill enough pond weed that native species can once again see the light and grow unencumbered.

“Once it’s in the lake, it’s there to stay,” Belden said. “There will never be full eradication of the plant. But we can at least control it and reduce its density so other plants come back.”

The herbicide needs to be applied before the native plants begin their growing season in June and the curly-leaf pond weed causes them to rot.

To keep residents up to date about the projects, the watershed district held community meetings on March 2 and March 7. The district has assembled an informational web page about the lake at capitolregionwd.org/comolake, with specific information about the two water treatment projects at tinyurl.com/ComoLake2020treatments.

Frederick Melo was once sued by a reader for $2 million but kept on writing. He came to the Pioneer Press in 2005 and brings a testy East Coast attitude to St. Paul beat reporting. He spent nearly six years covering crime in the Dakota County courts before switching focus to the St. Paul mayor's office, city council, and all things neighborhood-related, from the city's churches to its parks and light rail. A resident of Hamline-Midway, he is married to a Frogtown woman. He Tweets with manic intensity at @FrederickMelo.

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